Facsimile and static presentation processing – Static presentation processing – Attribute control
Reexamination Certificate
1999-05-03
2003-09-16
Lee, Thomas D. (Department: 2624)
Facsimile and static presentation processing
Static presentation processing
Attribute control
C358S003210
Reexamination Certificate
active
06621594
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a print data adjusting system, a print data adjusting method, and a software storage medium containing a print data adjusting program.
BACKGROUND ART
Recent advances in color ink-jet printer technology have made it possible to provide a high level of image definition for printed output of so-called photo-realistic image quality. In a color ink-jet printer capable of delivering such a high level of printout quality, color ink droplets are ejected to form dots of predetermined colors at desired points, thereby producing images in dot matrices. For color image printing, three primary color inks of cyan (C), magenta (M) and yellow (Y) or four color inks of cyan, magenta, yellow plus black (K) are used.
To realize photo-realistic quality, color reproducibility is of critical importance as well as fine dot formation. In the inside of a computer, colors are represented using red-green-blue (RGB) multi-level gradation data, whereas CMYK two-level gradation data is handled on a printer. Therefore, color space conversion and gradation conversion are performed for printout. Namely, in printing, CMYK two-level gradation is used while maintaining colors represented in RGB multi-level gradation on the premise that each dot is colored with specified density.
However, although color reproducibility is maintained with respect to print data on output, a volume per droplet of color ink may be different among print heads due to an instrumental error, resulting in each dot being colored with inconsistent density.
In the above-mentioned color ink-jet printer, if a volume per ink droplet ejected from its print head varies due to an instrumental error, each dot is not colored with specified density to cause a disadvantage of degradation in color reproducibility.
In order to circumvent this disadvantage, the inventors have examined an arrangement in which print data is adjusted in advance to compensate for an instrumental error and then a printing operation is performed according to the print data thus adjusted to improve color reproducibility. In this adjustment of print data, an adjustment table is used. For preparing an adjustment table, a patch pattern is printed in the entire gradation range using a reference print head which ejects each droplet of color ink in a specified reference volume, and also a patch pattern is printed in the entire gradation range using each print head having an instrumental error. Through comparison of patch patterns, error-free patch pattern combinations are determined, and thus a list of error-free patch pattern combinations, i.e., an adjustment table is created.
Although comparison of patch patterns is required, it is impracticable to compare patch patterns for all the colors to be reproduced. Therefore, the inventors have created an adjustment table for each element color. Although almost the same color reproducibility as with the reference print head has been attained in single-color printing, inconsistency has occurred in mixed-color printing.
In view of the foregoing, it is a principal object of the present invention to provide a print data adjusting system, a print data adjusting method, and a software storage medium containing a print data adjusting program for enabling accurate color reproduction regardless of an instrumental error among such parts as print heads.
DISCLOSURE OF THE INVENTION
For use with a printing apparatus which deposits element color recording materials in dot matrices on recording media to produce printed output of color images containing a plurality of element colors according to print data, a print data adjusting system arranged for adjusting print data to compensate for color variation due to inconsistency in quantity of recording materials used, characterized in that a predetermined degree of adjustment for compensating for inconsistency in quantity of each single color used is decreased at the time of color mixing through combinations of element colors to accomplish adjustment of print data.
In accomplishing the above-mentioned object of the present invention and according to claim
1
thereof, there is provided a print data adjusting system, for use with a printing apparatus which deposits element color recording materials in dot matrices on recording media to produce printed output of color images containing a plurality of element colors according to print data, which is capable of adjusting print data to compensate for color variation due to inconsistency in quantity of recording materials used, wherein a predetermined degree of adjustment for compensating for inconsistency in quantity of each single color used is decreased at the time of color mixing through combinations of element colors to accomplish adjustment of print data.
In the above-mentioned aspect of the present invention arranged as defined in claim
1
, a predetermined degree of adjustment for compensating for inconsistency in quantity of each single color used is attained to cope with inconsistency in quantity of recording materials used due to an instrumental error among printing apparatus, and then the above degree of adjustment is decreased at the time of color mixing through combinations of element colors in order to adjust print data.
In the result of experiments conducted by the inventors, it has been revealed that a degree of adjustment preset for single-color printing is too large when it is applied to mixed-color printing. Although this phenomenon is considered to occur due to a variety of causes, it may be inferred reasonably that a degree of adjustment for each element color becomes to have an increased effect through color mixing. Therefore, reproducibility in mixed-color printing can be improved by decreasing the degree of adjustment for each element color at the time of color mixing so that it is not used intactly for mixed-color printing. In this case, a mixed-color order is given in a range of a secondary color, tertiary color and so forth. As the mixed-color order increases, an effect corresponding to the degree of adjustment for single color is decreased. It is therefore possible to enhance color reproducibility by decreasing a mixed-color order for each dot to an optimum level.
There are two major applicable techniques for decreasing a degree of adjustment at the time of color mixing. In one of these applicable techniques, an optimum degree of adjustment for each pixel is used. As a concrete example according to claim
2
of the present invention, there is provided a print data adjusting system as claimed in claim
1
, which is characterized by degree-of-adjustment memory unit for storing a predetermined degree of adjustment for compensating for inconsistency in quantity of recording material used for each element color, degree-of-adjustment regulating unit for judging a mixed-color order for each dot and regulating the degree of adjustment to decrease to a level lower than in single-color printing when the mixed-color order becomes higher, and first adjustment unit for adjusting print data according to the degree of adjustment thus regulated.
In the above-mentioned aspect of the present invention arranged as defined in claim
2
, the degree-of-adjustment memory unit stores a predetermined degree of adjustment for compensating for inconsistency in quantity of recording material used for each element color to cope with inconsistency in quantity of recording material used due to an instrumental error among printing apparatus, and the degree-of-adjustment regulating unit judges a mixed-color order for each dot and decreases the degree of adjustment to a level lower than in single-color printing when the mixed-color order becomes higher. Then, the first adjustment unit adjusts print data according to the degree of adjustment thus regulated.
It is just required for the degree-of-adjustment memory unit to store a predetermined degree of adjustment so that inconsistency in quantity of recording material used for each element color can be compensated for, and degree-of-adjustment provision is implementable in
Kuwata Naoki
Maruyama Takashi
Brinich Stephen
Lee Thomas D.
Seiko Epson Corporation
Sughrue & Mion, PLLC
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